DNT+ keeps more than 600 ad networks and other Web trackers from depositing tracking cookies on your hard drive. It also tells you who they are. Period, full stop. (However, it won't do anything about tracking cookies that have already been deposited on your computer; you'll have to manually delete those.)

Getting DNT+ to work is painless -- download, click “Install,” and you’re done. I didn’t even have to restart my browser. Visit any site, and the DNT+ ticker in the upper right corner of your browser tells you how many Web trackers are embedded within it. Click the ticker to see the types of trackers and who they belong to.

For example, DNT+ detected 17 trackers on the very site where this column originated (ITworld.com).

Three of them are social media sharing buttons (Facebook, G+, Twitter). They will still work if you click them, but they won’t record the fact you’re looking at this page if you do nothing (which Facebook, at least, has been known to do).

Three are ad networks (Dedicated Networks, Quantcast, and AppNexus). By blocking them, DNT+ keeps them from capturing any information about you.

11 are classified as “trackers,” though most of these are also ad networks (like Doubleclick) as well as things like Google Analytics.

DNT+ also keeps a running tally of all the trackers it has blocked as you surf. It took me about 30 minutes of casual surfing to blast past the 100 mark. And that’s it in a nutshell. Really simple, highly useful, and did I mention it’s free?

Ghostery differs from DNT+ in a number of ways. The first is performance. DNT+ had no impact on how quickly pages loaded for me. In my experience, using Ghostery makes Web pages load a scosh slower (your mileage may vary).

With nearly 800 tracking companies in its database, however, Ghostery is a bit more thorough. At ITworld Ghostery found 20 trackers, including a half dozen DNT+ didn’t flag, but missed three trackers Abine did catch.

The biggest difference is that DNT+ just blocks these cookies outright -- ask no questions, take no prisoners. You have to tell Ghostery which tracking cookies you want to block, either individually by company or by category (advertising, analytics, etc).

The reason for that is simple. Ghostery is owned by Evidon, a company that’s trying to bridge the gap between ad networks and the people who are worried about Web tracking (aka, the Don’t Track Me Bro crowd). Evidon is behind the AdChoices campaigns you might see on some Web ads, which discloses information about what data each ad is gathering as you surf.

Evidon CEO Scott Meyer says fears about Web tracking are overblown, in large part because ad networks have no interest in personally identifying the people who are looking at their ads. He also sounds the usual warnings about how if tracking and targeted ads were regulated out of existence the “free” Internet as we know it would cease to exist.

(I have a problem with that argument, but I’ll save it for another post.)

The choice seems pretty simple to me. Hate Web tracking and all that it entails? Download DoNotTrackPlus. Want to know more about who’s tracking you without necessarily opting out of all tracking? Give Ghostery a spin, and look out for those blue AdChoices triangles as they proliferate across the Web.